ams_capacity

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

readOnlyHint=true already establishes this is a safe read, so the description's main added value is characterizing what the response contains — a capacity step, the month's top three hours, and per-hour headroom. That is genuinely useful interpretive context for a domain-specific metric, but it adds nothing about data freshness, timezone handling, or how 'this month'/'this hour' are anchored.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with the resource, with no wasted filler. But the second sentence restates 'capacity step' from the first rather than advancing information, and the phrase 'how much this hour could use before the step goes up' is dense and ambiguous compared to the space it occupies.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

A zero-parameter, read-only tool with an output schema and full schema coverage needs little more than a statement of what data comes back, which the description supplies. Nothing required to invoke it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is no parameter semantics for the description to carry; the baseline of 4 applies. The description correctly implies no input is required, consistent with the empty schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the resource contents (the grid's capacity step, the month's top three hours, this hour's headroom before the step rises), which is more specific than the bare tool name. However, it uses a domain term ('capacity step') without definition and never states an action verb, so an agent must infer that this fetches capacity data rather than, say, computing or setting a step. It also does not differentiate itself from ams_energy or ams_now.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no when-to-use guidance and no mention of alternatives, despite closely related siblings (ams_now, ams_energy, ams_history) that an agent must choose between. The only steer is implicit in the word 'capacity', leaving selection to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.